Sierra Leone's top Ebola doctor dies from virus

The doctor leading Sierra Leone's fight against the worst Ebola outbreak on record died from the virus on Tuesday, the country's chief medical officer said.

The death of Sheik Umar Khan, who was credited with treating more than 100 patients, follows those of dozens of local health workers and the infection of two American medics in neighboring Liberia, highlighting the dangers faced by staff trying to halt the disease's spread across West Africa.

Ebola is believed to have killed 672 people in Guinea, Liberia and Sierra Leone since the outbreak began in February, according to the World Health Organisation.